1. Field of the Invention
The present invention relates to a semiconductor device equipped with means for preventing breakdown of a circuit against unexpected high-voltage application such as electrostatic discharge.
2. Description of the Related Art
One main cause of the fault of integrated circuits is breakdown of a semiconductor element, an electrode, or the like due to electrostatic discharge (hereinafter referred to as “ESD”). In view of this, a protection circuit is disposed between a terminal and an integrated circuit, for prevention of the breakdown of integrated circuits due to ESD. The protection circuit is a circuit for preventing an overvoltage applied to the terminal by ESD or the like from being supplied to the integrated circuit. As typical examples of an element used in the protection circuit, there are a resistor, a diode, and a capacitor.
For example, according to Patent Document 1, a surge current generated by ESD is smoothed by a resistor that is interposed in a wiring which electrically connects a connection terminal and a semiconductor circuit. Further, in Patent Document 1, a diode is used in addition to the resistor, in a protection circuit. When ESD occurs, a discharge path of a surge current is formed by the rectification action of the diode to prevent the surge current from flowing into the integrated circuit.
[Patent Document 1]
    Japanese Published Patent Application No. 2000-58762 (FIG. 2)